• Title/Summary/Keyword: Liquid sensor

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Development of thin-film liquid-level sensors using AC heating method (교류 가열법을 이용한 박막 액체 레벨 센서 개발)

  • Hong, Jong-Gan;Choi, Sun-Rock;Kim, Dong-Sik
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1842-1846
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    • 2008
  • This work reports development of novel liquid-level sensors based on the $3{\omega}$ method. The sensors determine the liquid level by measuring the thermal response as in the conventional hot-wire technique. However the sensors employ an AC heating method to enhance the sensitivity, noise resistance and time response. Also, the microfabricated thin-film structure of the sensor provides mass-producibility as well as improved sensor performance owing to the increase in the surface-volume ratio of the sensor. Two different types of the sensor are developed: one for point detection of the fluid phase and the other for monitoring continuous variation of liquid level. Notable is that the performance of the sensor is not considerably affected by the liquid flow.

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Simultaneous Measurement of Liquid-level, Concentration and Temperature of a Urea Tank using Ultrasonic and Electrical Conductivity Sensors (초음파와 전기전도 센서를 이용한 우레아 탱크 수위, 농도 및 온도의 동시 측정 방안)

  • Choi, Byungchul;Kim, Taewook
    • Journal of Power System Engineering
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    • v.21 no.5
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    • pp.71-78
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    • 2017
  • The purpose of this study is to propose the basic data for the development of a sensor capable of simultaneously measuring the liquid-level, concentration and temperature of a urea tank using ultrasonic and electrical conductivity sensors for diesel vehicles with a urea-SCR system. It was found that the liquid-level of the urea tank using the ultrasonic sensor showed a good linearity with the actual liquid-level, and the urea concentration maintained good linearity in the range of 32.5 wt% to 10 wt%. It was an effective measurement of urea concentration to use the electrical conductivity sensor in the temperature range of $-10{\sim}22^{\circ}C$ and to use the ultrasonic sensor at $22^{\circ}C$ or more. Simultaneous measurement of concentration, liquid-level and temperature of the urea tank will be possible by attaching the electrical conductivity sensor and the ultrasonic sensor (split-type) to one sensor together.

Flexible multimode pressure sensor based on liquid metal

  • Zhou, Xiaoping;Yu, Zihao
    • Smart Structures and Systems
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    • v.28 no.6
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    • pp.839-853
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    • 2021
  • In this paper, a novel multimode liquid metal-based pressure sensor is developed. The main body of the sensor is composed of polydimethylsiloxane (PDMS) elastomer. The structure of the sensor looks like a sandwich, in which the upper structure contains a cylindrical cavity, and the bottom structure contains a spiral microchannel, and the middle partition layer separates the upper and the bottom structures. Then, the liquid metal is injected into the top cavity and the bottom microchannel. Based on linear elastic fracture mechanics, the deformation of the microchannel cross-section is theoretically analyzed. The changes of resistance, capacitance, and inductance of the microchannel under pressure are deduced, and the corresponding theoretical models are established. The theoretical values of the pressure sensor are in good agreement with experimental data, implying that the developed theoretical model can explain the performance of the sensor well.

A New X-Ray Image Sensor Utilizing a Liquid Crystal Panel (새 구조의 액정 엑스선 감지기)

  • Rho, Bong-Gyu
    • Korean Journal of Optics and Photonics
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    • v.19 no.4
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    • pp.249-254
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    • 2008
  • We developed a new x-ray image sensor utilizing a reflection-mode liquid crystal panel as its sensitive element, and tested its functionality by using it to obtain an x-ray image of a printed circuit board. In the liquid crystal x-ray image sensors hitherto reported, the liquid crystal layer is in direct contact with the photoconductive film which is deposited on a glass substrate. In the fabrication of the new x-ray image sensor, a liquid crystal panel is fabricated in the first step by using a pair of glass plates of a few centimeters thicknrss. Then one of the glass substrates is ground until its thickness is reduced to about $60\;{\mu}m$. After polishing the glass plate, dielectric films for high reflectance at 630 nm, a film of amorphous selenium for photoconduction, and a transparent conductive film for electrode are deposited in sequence. The new x-ray image sensor has several merits: primarily, fabrication of a large area sensor is more easily compared with the old fashioned x-ray image sensors. Since the reflection type liquid crystal panel has a very steep response curve, the new x-ray sensor has much more sensitivity to x-rays compared with the conventional x-ray area sensor, and the radiation dosage can be reduced down to less then 20%. By combining the new x-ray sensor with CCD camera technology, real-time x-ray images can be easily captured. We report the structure, fabrication process and characteristics of the new x-ray image sensor.

Study on the Sensor Development for Liquid Contamination during Delivery (이송 중 액체오염 검출센서 개발에 관한 연구)

  • Jeong, Yi Ha;Kim, Byung Han;Hong, Joo-Pyo
    • Journal of the Semiconductor & Display Technology
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    • v.15 no.2
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    • pp.70-73
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    • 2016
  • Previously proposed contamination detecting sensor was revisited for the investigation of the liquid tendency. Experiments revealed different output voltages for several kinds of liquid input, but showed same values for various flow rates of each liquid. The transmittance of the liquid was measured, and it is well correlated with the voltages. Linearity in values and the compensation of the sensor to sensor deviation were tried to obtain. And, long term test was performed as attached at the manufacturing equipment in the field.

A new reconfigurable liquid-metal-antenna-based sensor

  • Zhou, Xiaoping;Fu, Yihui;Zhu, Hantao;Yu, Zihao;Wang, Shanyong
    • Smart Structures and Systems
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    • v.30 no.4
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    • pp.353-369
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    • 2022
  • In this paper, a new sensor chip with frequency reconstruction range of 2.252 GHz ~ 2.450 GHz is designed and fabricated. On this basis, a self-designed "T-shaped" shell is added to overcome the disadvantage of uneven deformation of the traditional steel shell, and the range of the sensor chip is expanded to 0 kN ~ 96 kN. The liquid metal antenna is used to carry out a step-by-step loading test, and the relationship between the antenna resonance frequency and the pressure load is analyzed. The results show that there is a good linear relationship between the pressure load and the resonant frequency. Therefore, the liquid metal antenna can be regarded as a pressure sensor. The cyclic loading and unloading experiments of the sensor are carried out, and different loading rates are used to explore the influence on the performance of the sensor. The loading and unloading characteristic curves and the influence characteristic curves of loading rate are plotted. The experimental results show that the sensor has no residual deformation during the cycle of loading and unloading. Moreover, the influence of temperature on the performance of the sensor is studied, and the temperature correction formula is derived.

Sensor Fault Detection and Analysis of Fault Status using Smart Sensor Modeling

  • Kim, Sung-Shin;Baek, Gyeong-Dong;Lee, Soo-Jin;Jeon, Tae-Ryong
    • Journal of information and communication convergence engineering
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    • v.6 no.2
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    • pp.207-212
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    • 2008
  • There are several sensors in the liquid cargo ship. In the liquid cargo ship, we can get values from various sensors that are level sensor, temperature sensor, pressure sensor, oxygen sensor, VOCs sensor, high overfill sensor, etc. It is important to guarantee the reliability of sensors. In order to guarantee the reliability of sensors, we have to study the diagnosis of sensor fault. The technology of smart sensor is widely used. In this paper, the technology of smart sensor is applied to diagnosis of level sensor fault for liquid cargo ship. In order to diagnose sensor fault and find the sensor position, in this paper, we proposed algorithms of diagnosis of sensor fault using independent sensor diagnosis unit and self fault diagnosis using sensor modeling. Proposed methods are demonstrated by experiment and simulation. The results show that the proposed approach is useful. Proposed methods are useful to develop smart level sensor.

Development of Three-ring Conductance Sensor based on Flexible Printed Circuit Board for Measuring Liquid Film thickness in Two-phase Flow with High Resolution (고정밀 2상유동 액막두께 측정을 위한 연성회로기판 기반 3-전극 센서 개발)

  • Lee, Kyu-Byoung;Kim, Jong-Rok;Euh, Dong-Jin;Park, Goon-Cherl;Cho, Hyoung Kyu
    • Journal of Sensor Science and Technology
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    • v.25 no.1
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    • pp.57-64
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    • 2016
  • To understand a two-phase flow, a liquid film thickness is one of the important factors. A lot of researches have been performed to measure liquid film thickness with various approaches. Recently, an electrical conductance method which uses the conductivity of the liquid film has been widely applied on measuring the liquid film thickness. Though the electrical method has an advantage in high spatial resolution, as the conductivity of liquid can be affected by its temperature variation, the conventional electrical conductance methods have a limitation in being applied on varying temperature conditions where a heat transfer is involved. The purpose of this study is to develop a three-ring liquid film sensor that overcomes the limitation of the conventional method. The three-ring conductance method can measure the film thickness regardless of temperature variation by compensating the change of liquid conductivity. Considering its application on a wide range of conditions such as high temperature or curved surfaces, the sensor was fabricated on flexible printed circuit board (FPCB) in this study. This paper presents the concept of the measurement method, design procedure, prototype sensor fabrication and calibration results.

Liquid level measurement system using capacitive sensor and optical sensor

  • Shim, Joonhwan
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.7
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    • pp.778-783
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    • 2013
  • Measurement of liquid level in storage and processing vessels, tanks, wells, reservoirs and hoppers is commonly needed. The several different ways to measure the liquid level of oil or water tank have been provided such as an electrostatic capacity, a supersonic waves and an optical science etc. In the study, we have constructed the stable and efficient measurement system to measure the level of liquid at real-time and to get accurate measurement of the maximum and minimum level of the tank. For this purpose, we suggest double sensing methods by adopting both capacitive and optical sensing. The experimental results, presented in this paper, illustrate the effectiveness of the proposed method under different sensing methods.

Measurement of Thermo-Optic Coefficient of a Liquid Using a Cascade of Two Different Fiber Bragg Gratings

  • Kim, Kwang Taek;Kim, In Soo
    • Journal of Sensor Science and Technology
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    • v.22 no.2
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    • pp.95-99
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    • 2013
  • We proposed and demonstrated a fiber optic sensor for detecting the thermo-optic coefficient of a liquid, based on a cascade of two different FBGs. One of the two FBGs was etched, and its cladding was removed, for evanescent wave coupling with an external liquid. The Bragg wavelength of the non-etched FBG was used as a reference for the temperature of the surrounding liquid. The refractive index (RI) and thermo-optic (T-O) coefficient of a liquid can be detected from the difference between the Bragg wavelengths of the two FBGs, and the variation of the difference in accordance with temperature.